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P F Davis

Publications and source records attributed to P F Davis.

46 records · Page 3Linked to original sources
PubMed1984

Isolation and characterization of salt-soluble cross-linked elastin from vascular tissue.

Fibrous elastin, a stable and important constituent of vascular tissue undergoes degenerative changes including fragmentation in atherosclerosis. The nature of the protein fragments produced during the in vivo degradation of elastin is largely unknown. From salt extracts of haemodynamically stressed tissue in sheep, polypeptides were isolated by hydrophobic interaction chromatography. These polypeptides coacervated and had amino acid compositions similar to those of in vitro solubilized elastins. The presence of the cross-links, desmosine and isodesmosine, in the isolated material indicates that the fragments originated from fibrous elastin and that cleavage of cross-links is not necessary for the solubilization of the fibre.

Amino Acids↗
PubMed1983

Purification of salt-soluble cross-linked elastin by hydrophobic interaction chromatography.

The hydrophobic protein elastin, which is a major constituent of vascular and lung tissue is fragmented in several pathological conditions. The nature of the soluble fragments is not well understood. Such fragments bind to alkyl chains linked to agarose. Elution, which is effected by dimethylformamide and sodium dodecyl sulphate, is optimal from the decyl-agarose column. Dialysis of the eluates against buffered sodium chloride precipitates elastin, thus further purifying the salt-soluble cross-linked elastin.

Amino Acids↗
PubMedDate not supplied

Platelet derived growth factor-BB induced calcium transients in cultured human peritoneal mesothelial cells.

The peritoneal membrane is used as an artificial dialysis organ for patients with end-stage renal failure during continuous ambulatory peritoneal dialysis (CAPD). Resident peritoneal mast cells may influence the course of the inflammatory process during acute infection or prolonged exposure to dialysate in a paracrine fashion, with the release of preformed mediators, including platelet derived growth factor (PDGF), which may activate human peritoneal mesothelial cells (HPMC) and other peritoneal cells. PDGF receptor interactions have multiple intracellular effects, typified by cell proliferation, protein synthesis, cytoskeletal organization, extracellular matrix turnover, and angiogenesis. PDGF may mediate HPMC inflammatory response by stimulating cytokine release. The presence of transcripts for both PDGF-B polypeptide and PDGF-beta receptor in cultured HPMC was confirmed using a reverse transcriptase-polymerase chain reaction. To investigate the activity of PDGF-beta receptors in HPMC, the authors examined intracellular calcium (Ca2+(i)) mobilization in HPMC in response to PDGF-BB (100 ng/ml), histamine (1.0 mmol/L), and 4-brA23187 (1.0 micromol/L) using the calcium indicator, fura-2. HPMC calcium mobilization in response to PDGF was assessed in Krebs-Ringer saline, with and without added external calcium (Ca2+(ext)). HPMC responded to PDGF with a transient rise in Ca2+(i) (approximately 1.6-fold) that returned to an elevated resting value. In the absence of Ca2+(ext), PDGF produced a Ca2+(i) transient indicative of Ca2+ release from intracellular stores. These results suggest that HPMC have functional PDGF-beta receptors that may bind and respond to PDGF in both an autocrine and paracrine

Becaplermin↗
PubMedDate not supplied

Arthroscopic acromioclavicular joint resection. An anatomical study.

Distal clavicle resection has been an effective procedure for treatment of acromioclavicular arthritis. The conventional open surgical technique involves deltoid detachment and reattachment, which may cause postoperative weakness and requires protection during the postoperative period to allow for healing. Arthroscopic acromioclavicular joint resection has the theoretical advantages of no deltoid disruption and a shorter rehabilitation period. The purpose of this study was to compare open versus arthroscopic acromioclavicular joint resection in a laboratory setting. The goals of acromioclavicular joint resection in this study were to remove 5 mm of the medial acromion and 10 mm of the distal clavicle. Acromioclavicular joint resections were performed on 10 cadaver shoulders (5 open resections and 5 arthroscopic resections). Open resection was successful at 10 of 15 distal clavicle locations and 14 of 15 medial acromial locations. Arthroscopic resection was successful at 14 of 15 distal clavicle locations and 10 of 15 medial acromial locations. The combined bone resection averaged 14.8 mm (+/- 1.99 mm) for the open technique and 14.8 mm (+/- 2.58 mm) for the arthroscopic technique. The combined bone resection was 1.5 cm or more in all of the measured locations for the open technique and in 14 of 15 measure locations for the arthroscopic technique. There was no statistically significant difference between the two groups. In the laboratory setting, acromioclavicular joint resection was performed effectively and predictably with arthroscopic instruments. Arthroscopic bone resection was comparable to open bone resection.

Acromioclavicular Joint↗
PubMedDate not supplied

Oral shark cartilage does not abolish carcinogenesis but delays tumor progression in a murine model.

BACKGROUND: Shark cartilage and shark cartilage extracts have been reported to have anti-angiogenic and anti-neoplastic properties. This study reports the effects of oral administration of powdered shark cartilage on tumor progression in a murine renal tumor model. MATERIALS AND METHODS: Renal tumors were induced in CBA female mice by a single bolus of IV streptozotocin. 57 mice were fed shark cartilage and the numbers and rate of development of dysplastic convoluted tubules, papillary and solid renal epithelial tumors was compared with 57 control mice over an 88 week follow-up period. RESULTS: In the shark cartilage fed group dysplasia was first observed after 23 weeks (control 19 weeks), papillary tumors after 24 weeks (control 23 weeks) and solid tumors after 55 weeks (control 19 weeks). There was no significant difference in the rate of development of dysplastic tubules between test and control animals. The development of papillary and solid tumors was significantly delayed in the test group. CONCLUSIONS: In this tumor model oral shark cartilage delays, but does not abolish, tumor progression.

Administration, Oral↗